It was a vivid simulation Tuesday of every parent’s and every teacher’s worst nightmare: A shooter on the loose inside a school, chased by police hoping to stave off tragedy and death.

But at this school in Methuen, Massachusetts, authorities had the benefit of a powerful new technology – a gunshot-recognizing and –locating technology developed by Shooter Detection Systems LLC of Rowley, from Pentagon and Raytheon Corp. technology. The moment that the shooter’s gun went off, the SDS system instantly recognized that it was a gunshot, and from sensors located in the school walls, sent messages to police and school authorities idenfying down to the classroom where the mock shooter was.

Methuen Police asked the media for security reasons not to name the school where the system has been deployed, wanting not to attract a deranged gunman looking to put the system to the test or highlight which schools lack the same technologicaly protection. Police Chief Joseph Solomon said authorities have been extremely pleased with how well the system performed Tuesday and in earlier tests. Besides giving them instant notification, potentially minutes before someone knows what is going on and can call 911, Solomon said the technology answers questions like "where is the shooter? Has the shooter changed his location? How many shots have been fired? Is the shooting ongoing? And, very important, what is the shooter’s direction of travel?"

SDS president and CEO Christian Connors said the "Guardian Indoor Active Shooter Detection System" would typically cost about $50,000 to $100,000 per school, fully installed, depending on its size and configuration. Connors said the company hopes to announce a deployment at an airport in coming weeks. Unfortunately, based on recently mass-casualty shootings around the world, it’s all too easy to imagine how many other locations could be protected by such a system – cinemas, sports arenas, shopping malls, railroad and subway stations, and more.

The technological brains of the system is the same as what’s been deployed to protect soldiers and Marines in Iraq and Afghanistan more than 10,000 times, U.S. Rep. Niki Tsongas, a Lowell Democrat who serves on the Armed Services Committee, said at a press event showcasing the technology. Based on lots of real-world testing and an extensive library of the "acoustic signatures" of gunshots – to distinguish them from other explosive sounds – Connors said it’s proven to be completely reliable in identifying gunshots and not getting tripped by other sounds.

"We have not had the system false-alert once in any location, or been able to false-alert in tests," Connors said.